Months before global stock markets were roiled by volatility in August, U.S. financial regulators asked major banks to test how their balance sheets would fare under extremely adverse conditions and present plans for raising emergency capital if the need arose, say people familiar with the matter.

AP

Late in the spring and over the summer, officials from the Federal Reserve, the Federal Deposit Insurance Corporation, and the Office of the Comptroller of the Currency privately asked a slew of banks—including Bank of America, JPMorgan Chase [JPM34.300.86(+2.57%)], Citigroup, and Morgan Stanley[MS15.780.45(+2.94%)]—to stress-test their capital levels and see if additional funds could be needed, these people say.

One scenario that at least two banks were asked to run, said two of these people, was a fall 2008-type stock market rout. The banks were asked to present plans, these people added, for raising emergency capital in case a sudden need cropped up.